Chuck



C. R. PRATT.

Feb. 20, .1923.

CHUCK.

FlLED JUNE 4.1920.

4 SHEETSwSHEET l.

Feb. 20, 1923. 1,446,062. v 0 R. PRATT.

' CHUCK. f

FILED JUNE 4. 1920. 1 4 SIHEETSYSHVEET (2.

lave-31,303?) Charles EJ92 051??? E [301/24, 1% M M W c. R. PRATT. CHUCK.

FILED JUNE 4. 1920.

Feb. 20, 1923. 1

4 SHEETS-SHEET 3 C. H. PRATT.

CHUCK.

FILED JUNE 4, 1920.

I Feb. 20, 1923.

4. SHEETSSIHEET 4.

Patented Feb. 20, 1923.

After CHARLES n rnnrr, or MONTCLAIR, nnw'rnnsnY, nssrenon TO rnn E. ams-a."

CONNECTICUT, A conrona'rron on con son COMPANY, or wnvnsoe Loc s; nnorrou'r. v

Application filed June a,

To 'all wkoin c't may concern: Y Be it known. that'I, CHARLES R. Pna'rr, a citizen of the :United States, and a resident of Montclair, in the county of Essex, State" ters on the drawings representing like parts.

This invention pertains to improvements in chucks. It'is among the objects of the invention; to provide a chuck, primarily, though not'exclusively, useful in connection with the turn- .ing of work on lathe centers.

In'the' drawings, which show a preferrer form of one illustrative embodiment of my:

invention p I I Figure lis afront elevation of a chuck; Fig. 2 is a section, partly inelevation, on

the line 22 of Fig. 1; I

Fig. 3 isa section, partly in elevation, on'

the line 33 of Fig. 2;

F igut is a plan view ofthe chuckshown inFig.l;

Fig. 5- is a section on the-line'5--5' of Fig.3;

Fig. 6. is a diagrammatic view showing a preferred form'of spring and assembly fixture for use in connection with'the assembly thereof with other parts of the chuck;

Fig. '7 is a view siinilar to Fig. 3,"some of the parts being omitted, and showing the rclation of parts of the chuck when gripping work under heavy pressure; and

F 8 1s a diagrammatic view showing a portion of the parts shown "in Fig. 7' while gripping work under a lesser pressure. v

Referring to the drawings and to the preferred form of my invention selected for illustrative purposes, I have shown a chuck primarily useful for turning'work on centers, thou h many features of'm invention'mav e v y t be useful in other connections. The specific form of my invention illustrated includes a chuck body, preferably including a rim portion 9,a face portion 10 and a hub portion 11, said body preferably carrying in guided relation to the face portion a ,pluralityof slides 12, formiiw a portion of the, jaw

vmechanism, but preferably. supplied with work-gripping jaws 13,-which may be and preferably are adjustably mounted on the slides 12, such adjustment preferably being,

CHUCK.

ping aws 13 in guideways on the slides-12 and by providing clamping means typified by the. screw 14' for binding said jaws in I any desired adjusted relationshipytozthe slides 12. The details of the preferred form of mounting of the jawsv 13 onrthe slides 12 are best shown inFig. 4:, wherein the clamping nut 15"is slidable inaguide slotin the against flanges 16 onthe slide 12. 1 1

"slides 12, the tightening of the screw 14;: pressing the clampingnut 15 and the jaw 13 The preferred form of "j aw mounting before described is particularly useful in con-s nection with chucks of the universal type,? l wherein the jaws are adapted to be moved coordinately by any type ofl universal jaw operating mechanism, because the absence; of

- the usual screw or other adjustment: precludes the'p utting of undue strainwon the universal mechanism which is" ordinarily likely to result from the tighteningofindimvidual screw "adjustments on each jaw separately' pursuantto the" application of initial pressureof the jaws to the work by th iver'sal mechanism.

v H580 Any suitable form of work-gi ippingbit may be provided in connection with the jaws 18, but I prefer to provide the bits 17 (best shown in Figs. Land 2),sueh bits preferably engaging the work at a'point out'ofline withthe center'lo'f movement offthe jaw and preferably behind the'center of movement 'of'the't jaw considered with reference to thedirection of rotation of the chuck- "Th e bitfs 17 are preferably pivotallyfmountfed-as on'studs- 18, so that the bits may, "accommod'ate" themselves to tapering-work. Each bit preferably provides line contact with/(he work, Y and is preferablyadap'ted to be{ turned *into X a plurality of positions to. provide a change 'of working edges, herein shown as four, any

one of which may be brought into operative.

position by turning of the" removal; of 'its'stud 18. j The chuck illustrated is primarily,thou gl'1-' not exclusively, intended for turning work v 'on centers, and to this end Ihave provided pur s 'ijant to a an aperture extending through the axis of the chuck so that a lathe center'held-in the spindle of the lathe, may project through the chuck and into proximity to the'jaws of the chucln The lathe spindle, illustrated .in, the drawings, is numberedmj I elements 22.

In the preferred form of my invention illustrated in the drawings, the pressure of the jaws on the work is resilient, and I preferably provide this resiliency by spring means, herein typified by the distortable ring 21 connected to the jaws by thrust means herein typified by the thrust elements 22, which may operate as toggles and which preferably include features more usually associated with cam mechanism, as more fully described hereinafter. The thrust elements 22 are connected to the slides 12 by pivot pins 23, and the thrust elements 22 bear against the'interior of the spring ring 21. The angular position of the thrust elements 22 may be changed to operate the jaws and to put pressure on the spring ring in any suitable way, butl prefer to perform this by providing a spider 2%, having means engaging each of the thrust elements 22, such means being typified by the pins or projections 25 located at each side of each thrust lement. The spider 2a is preferably adaptedto be oscillatedtochangethe angle of position "of the thrust elements; such oscillation being conveniently effected .by eccentric means 26, best shown on Figs. 1, 3 and 5.

Vhen the eccentric 26 is turned by the wrench 27, shownin Fig. 1, the eccentric slide'28 oscillates the spider 24:, thereby changing the angular position, of the thrust As viewed in Fi 3, the thrust elements 22 are in work-releasing position, While the. relation of the parts pursuant to "shifting of the spider 2 is shown in Fig. 7.

As the spider' 24t straightens thethrust eleme-nts' 22, the initial movement produced thereby is a shifting of the pivots 23 toward the work until the-jaws engage the work. The pivots 23 then-become'fixed points, or substantially fixed'points, and the remainder of the movement of the toggles or thrust elements' 22- is effective to distort the spring ring 21, thereby applying to the pivots 23 I and =the-jaws connected thereto a resilient pressure which is relatively constant. though it may be somewhat greater where the work gripped is of -relatively large size in proportion to the adjustment of the work-gripping jaws than where the work gripped is of somewhat-smaller size with reference to the adjustment of the work-gripping jaws. The distortion of the ring illustrated in Fig. 7 is such as to produce a very considerable pressure onthe work, while the distortion of the ring shown diagrammatically in Fig. 8 is such as to produce a relatively less pressure onthe work.

The thrustelements-22 are preferably, as shown, provided with cam surfaces at their outer ends, so that as their angular position relative to the axis of the jaws is changed,

the effective lengthgof the thrust elementsis changed. The shaplng of these cam surfaces is preferably such as to preserve a more or less constant degree of angularity between the point of contact of the thrust elements on the spring means, the axis of the plvots I c c axis of th pivots 23. Where this preferred construction is used, andthe effective angle of the toggle is maintained more or and a radial line passing through the be and preferably is formed by winding spirally, preferably in close'adjacency to one another, a plurality of turns of a single band of spring metal. The spring may be and preferably is kept wound by securing the ends thereof in any suitable way, typified by the riveting together of the outer end thereof to the adjacent spire thereof as by rivets 30.

It is highly desirable that the spring means be under initial stress,- so that from the very initiation of distortion thereof a considerable resistance to distortion will be provided, and to'this end I may distort the ring somewhat during assembly withthe rest of the chuck, as by forcing the ring over the pins 25 on the spider 24. This distortion may conveniently be effected by an assembly tool, best illustrated in Fig. 6, such assembly tool being adapted to force the spring responding to the number of jaws to be used on the chuck. The pins .25 are preferably proportioned to maintain. at least a por-.

tion of thisinitial distortion of the spring,

Where, as in the preferred construction illustrated, the thrust elements '22 have ,no

positive connection, to, the spring. means, I

into more or less polygonal form corpreferably provide'means for maintaining "the thrust elements in, contact with the th jaws when pressure of the spring ring.

on the toggles is relieved.

The preferred form of chuck shown for illustrative purposes is, as before stated, primarily, though not exclusively, for turningwork on centers, and to this end the jaws and the mechanism for operating the jaws are preferably of the floating type, so that the position of the jaws relative to one work by the position of the gripped surfaces of the work determined by the lathe center. I also preferably mount the spider 24: for free floating movement..-- lVhen the slides 12 are fully opened by 'operation'of the floating mechanism controlling the same, the float is, in a sense, discontinued and the position of the slides and co operating parts relative to the chuck bod yis determined in such a way as to more or less center the jaws and insure an ample aperture between the jaws for the introduction of. the work in proper relation to the lathe center. This determining of the slide position may conveniently be effected by limiting means whereby the outward movement of each slide is determined and by providing a sufficient throw of the slides to insure the movement of all the slides to the limit of their outward movement. Such limiting means may take the form of keys 33 securedto the slides, adapted to abut against the outer ends 34 of slots in or connected to the chuck body. I

In the preferred *form of chuck illustrated, the toggles 22 are held in assembled relationship with the slides a 12, and the spring ring 21 is held in place by the spider 24, the spider 24 being held against displace ment in a direction toward the rear of the chuck by means typified by the nut .34, which may be threaded-to the hub 11 of the chuckbody. In the preferred form of my invention, the spider 24 is free to float relafree to swing between the slides 12 and spi der 24, preferably substantiall fill the. space tive to the chuck'body. I

The toggles or thrust elements 22, while between the slide and the spider so that the pivots 23 are in a measure relieved of bending strain by reason of the support of the parts 22 between the slides and spider. I

The back ofthe chuck is preferably closed by a plate 35, which may be bored and tapped or otherwise fitted for attachment to the lathe spindle. When the chuck is on the spindle, the back of the chuck is entirely closedand there are preferably. no openings through any part of the chuck body through which lubricant confinedin the chuck body may. escape. This tightness may be insured by the provision ofpacking 36 around the spindle and by the provision: of packing 37, 38 at either. end of the slides. The floating of the jaw-actuating mechanism in the to itsaxis for throughout a subs but not chuck body assiststhe distribution'ofhe-avy lubricant to all workingparts'thereof, and

the. pivots ofthetoggles, I

especially to the leaves .of the spring and While I have "shown ands-described af and reversalof parts, even changes'in the mode of operatiominaybe made {without departing from the scope, of my inventiomk which is best defined in the following claims.

1. A chuckc0mprising,in combination, a

plurality of work-gripping{elements and a spirally wound, laminatedclosed spring ring exertingzpressure in a pressing said elements. against, the Work.

2. A chuck comprising,in combination, a

M I V plurality of worl' gripping elements and a spirally wound, laminated closed spring. ring exerting pressure inja direct-ion transverse to its axis for pressing said elements-against the Work, the adjacent spires. of said spring lying against each other. '3. A chuck comprising-in combination, a plurality of work-grippin elements-and a spirally wound -laminatec l closed, spring ring exerting pressure in a direction transverse to its axis for pressing said elements against the work, the adjacent spires ofsaid spring lying against each other a11cl hel l' against uncoiling movement. v I f r 4:. A chuck.comprising,infcomb-ination, a jaw, and a swinging thrust element connect-- direction transverse g ed to said jaw, said thrust element having a i cam surface shaped; to transmit, pressure directly in a substantiallyradial direct-ion antial portion of its swinging movement.

rectilinearly shiftable jaw, a swinging thrust element connected ,tosaid element-having a cam surface providing varying effective lengths of the thrust element as the thrust element is swung to act-u ate reciprocation of the jaw; 6, A chuck 7 comprising, in combination, a plurality of'jaws, laterally swinging thrust elements'connectedto said jaws, oscillatory means for swinging said thrustelements, and a spring ring surrounding said thrust elev .105 5. A chuck comprising, in combination, a

jaw, said thrust I ments', said thrust elements bearing against s positively co nnecte dil to} said spring ring. 1

plurality of jaws, swinging thrustelements., connected to sa d aws, oscillatory means for s i 2 7. A chuck comprising, incomb ination, a;

elements, saidf, thrust elements I bearing a ai t ring. '8. Achuck comprising, in combination, a plurality of jaws, swinging thrust elements but not positively connected to said i tion completely connected to said jaws, means for swinging said thrust elements, and distortable spring means pressing against the outer ends of said thrust elements, said thrust elements hearing against but not positively connected to said spring means.

9. A chuck comprising, in combination a aw, spring means constantly urging said jaw into work-releasing position, operative control means for actuating said jaw toward the work and spring means between said operative control means and said jaw tor moditying the action of said operative control means into a yielding instead 01: positive pressure.

' 10. A. chuck comprising, in combination, a jaw, a pressure-applying spring for determining the pressure of the jaw on the work, a thrust element bearing against said spring and connected to said jaw, and second spring for maintaining said thrust element against the firstnamed spring during the releasing action of the aw. i

11. In a chuck, a plurality of. jaws,'toggle means for actuating said jaws, a body, and an oscillatory spider for swinging said toggles, and-spring means carried by said spider for limiting the pressure applied to the jaws.

12. in a chuck, a plurality of jaws, a spider, spring means normally held under stress by said spider, and means between the spring means and the jaws which increases the stress on said spring means when said jaws grip the work.

13. in a chuck, a plurality o't jaws, a ringlike-spring, means normally distorting said spring to provide initial stress, and thrust elements between the spring and jaws, said thrust elements angularly shift-able to actuate the jaws and to increase distortion of the spring when the jaws are forced against the work.

14. A chuck having a body portion, jaws movably guided in said body portion,"and a floating portion in said body portion operatively connected to said jaws and permitting relative eccentric shitting thereof while guided in said body portion, said body porsurrounding and enclosing said floating port-ion whereby lubricant contained in said body portion may be distributed through the working parts of the floatin portion as said floating portion is moved relative to said body portion. I

15. A chuck comprising, in combination, a plurality of jaws, thrust means for moving said jaws toward the work, and spring means compressed when said aws grip the work and expansible for thrusting said jaws and thrust means away from the work.

16. A chuck comprising, in combination, a plurality of jaws, thrust means for moving said jaws toward the work, and a ring-like spring means compressed when said jaws grip the work and expansible for moving said awe and thrust means away from the work.

17. i i chuck comprising, in combination, a plurality of jaws, thrust means for moving said jaws toward the work, and cylindrical, helical spring means compressed when said jaws grip the work and expansible for moving said jaws and thrust means away from the work.

18. A chuck comprising, in combination, a body, jaw-carrying slides guided in said body, transversely floating means for moving said slides toward the work, jaws slidably and adjustably mounted in said slides and clamping means for holding said jaws in adjusted position on said slides, whereby moi'ement of said jaws under pressure toward the work is limited to the range of movement and to the pressure of said transversely floating means. I

1.9. A chuck comprising, in combination, a body, jaw-carrying slides-guided in said body, transversely floating means for moving said slit es toward. the work, said'transversely floating means including spring means limiting the pressure applied to the work, aws slidably mounted on said slides.

whereby movement of said jaws under pressure toward the work is limited to the range of movement of the transversely floating means, and whereby the application of increased pressure to the jaws by adjustment of said jaws on the slides after work-gripping operation of said transversely floating means is. precluded.

20. A chuck having a body providing an external flange, a face portion and a central hub; jaws slidably guided in said body; and transversely floating means surrounding said hub for actuating said jaws.

21. A chuck having a body providing an external flange, a face portionand a central hub; jaws slidably guided in said body:

transversely floating means surrounding said.

hub for actuating said jaws; and means on said hub opposing dis 'ilacemeut ot said floatlOO ing means in a direction toward the rear 01 said body.

22. A chuck comprising. in combination, a body including a face portion and a hub portion, jaw slides movable in guides in said iia-ce portion, toggles rearwardly of said :l ace portion and connected to said slides, a plate rearwardly of said toggles, andmeans on said hub portion opposing displacement of said plate in a direction toward therear of said body, tion transverse to the axis of the chuck.

23. A chuck comprising, in combination, a body including a -face portion and a hub portion, jaw slides movable in guides in said face portion, toggles rearwardly of said face said plate free to float in a direc portion and connected to said slides, a plate rearwardly ofsaid toggles, and means on said hub portion opposing displacement of and connected to said slides, a plate rear wardly of said slides and means attached to the chuck body opposing displacement of said plate in a direction rearwardly of the body, said plate free, to float in a direction transverse to the axis of the chuck.

25. A chuck comprising, in combination, a body including a face portion, jaw slides movable in guided relation to said face portion, toggles rearwardly' of said face portion and connected to said slides, a" plate rearwardly of said slides and means attached to the chuck body opposing displacement of said plate in a direction rearwardly of the body, said plate holding said toggles in "assembled relation to said slides.

'26. A chuck comprising, in combinatioma body, jaws, a floating spider, and means. for

oscillating said spider to actuate movement of thejaws. 7 v

27. A chuck comprising, in combination, a body, jaws, a floating spider, and means for oscillating said spider to actuate movement of the jaws, said means permitting said-t.

spider to float freely. in all directions during oscillation thereof; 7 I

28. In a chuck],.the combination with a body portion and jaws movable relative thereto, of a floating member having a motion generally concentric to the axis of the chuck but rectilinearly shiftable in aplane perpendicular to said axis, and a toggle pivoted at one end to" said jaw and at the other end bearing. against said member.

29. In a chuck, the combination with a body portion and jaws movable relative thereto, of a floating me1nberhaving,a'motion generally concentric to' the axis of the chuck but rectilinearly shiftablein a plane perpendicular to said axis, a toggle pivotedat one end to said jaw and atthe other end bearing against said member, and means for turning said member relative to the chuck.

In testimony whereof, I have signed my name to this specification. I

, CHARLES R. PRATT. 

